The next great civil rights battle may be whether America's old racial categories can keep up with its future.

Why it matters: The U.S. is heading toward a more Latino, Asian, Black immigrant and multiracial future — and the rules for counting race will help decide who gets political power, civil rights protections and public resources.

Zoom in: Two massive generational shifts will redefine the nation...

• Multiracial dominance: Multiracial Americans are on track to likely dominate the population over the next two centuries.
• Trade with Latin America could blur lines of migration and citizenship.

State of play: For decades, federal racial categories have been the foundation for enforcing anti-discrimination laws, drawing political districts and measuring inequality.

• If identity becomes completely fluid, or if old boxes break down, the very legal tools used to protect marginalized communities could weaken.

The bottom line: The question isn't whether America will diversify, but whether a civil rights enforcement system built on 20th-century boxes can govern a 22nd-century nation.

This story is part of an Axios Deep Dive on the policy debates shaping America's future. Read more in the series:

America's killer app: The dollar as the world's currency

AI oversight gap could leave a lasting legacy

The power decisions that could shape the next century

The fight over America's vaccine future

ABC's FCC battle could redefine press freedom